MacMost Now 278: Layering Audio in iMovie 09

Gary Rosenzweig: Hi this is Gary with MacMost Now. On today's episode let's look how to layer and edit audio in iMovie 09.
So iMovie 09 allows you to do a lot with audio, including being able to create layers of audio -- different things like the audio from your video, some music, sound effect, things like that. Let's go and take a closer look.
OK, so here's an iMovie project. I'm gonna go ahead and select and drag a clip and put it in the project up here. Now, I've got audio in this already but I scratch it or if I play it you can here the audio. So now what I want to do is I want to add another layer of audio on top of that.
Now, I can drag an audio file from the finder of I can go ahead and select the audio section here on the right. And I can go ahead and look through the things I have in iTunes. I can look through things I've saved from Garage Band. I can also look through sound effects and various bits of music from iLife and iMovie itself.
So for instance, I can select the iLife sound effects and go to jingles and at the bottom here I'll see various different pieces of music that come with iLife. So I can go ahead and pick one of these and preview it. I can go ahead and drag that to the project here.
I can add it to the entire project, which is what the green here is indicating, or I can go ahead and add it into the clip right here. And it'll put it right here. You can see clearly where the starting point is for it. Now, if I play it, I'll here both me talking from the video and I'll hear the music itself.
Now, I can go ahead and make this audio a little quieter by clicking on the tool area there, going to audio adjustments, and then I can go ahead and adjust the volume. So I can bring this volume down.
Now, you can adjust this audio in other ways as well. If I go to audio adjustments again, not only can I adjust the volume, but I can create something called ducking. What ducking will do is it'll basically make this the dominant piece of audio and it'll go and reduce all the other tracks. So I can turn that on and this will take all the other tracks down to 15% of the volume. I could take it down to nothing if I really want to cut out all the other audio from all the other tracks.
Now, I can also adjust the fade in and fade out for the piece of audio. I can set it to manual and I can set it down to nothing if I just want it to abruptly start playing or I can increase it up to five seconds.
Now, I can go ahead and add yet another layer if I want. I can add another song or say I can go ahead and add a sound effect to the same area. And you can see it appears there in another layer. I can go ahead and adjust the audio for that as well to whatever I want -- volume increase, fade in, fade out, that kind of thing. And now all of the audio will play. I'll get me talking in the video. I'll get music and I'll get the sound effect.
Now, you can go ahead and separate the audio from a piece of video like this by selecting the video and going to edit and then detach audio. This will create a layer of audio that is synced perfectly with this piece of video here.
Now, since it's completely separated from the video, you could actually go ahead and do things with it. Let's get rid of the rest of this audio here. I can actually go ahead and trim it and shift it. I can shift it slightly and now the audio will be off with the video.
One of the neat things you can do with this, though it's not very useful, is you can then go into clip adjustments just for that piece of audio and you can actually change the speed or even reverse the audio there and you get a really strange piece of audio.
Another thing you can do with audio - and this doesn't matter if you've split it from the video or not -- is you can go ahead and normalize this under audio adjustments. And what normalize does is it basically increases the volume of the clip so that it's as loud as can be without actually distorting it.
This really helps if you've got a very low microphone volume or you've got different clips you're going to use in the same movie that have different levels of volume. Going ahead and normalizing each clip is a very quick way to get the volume set to about the same throughout your entire project.
Another thing you can do is you can take a piece of audio, add it to the sequence, and you can go and trim it by using the clip trimmer right here. Select that and now you can see the wav form and you can make out little bits of the sound using the wav form. You can trim it to get a very specific piece of audio, like maybe this just one click here. Hit done and now you've got that one click in the sound instead of the entire thing.
One common thing you may want to do is mute the volume in just one section of your video. One way to do that is simply to go ahead and split the video in many places. So you can select an area in the video and then you go ahead and select split clip, which is Shift + Command + S. So for instance, I go right here, I do Shift + Command + S. It splits the video. I do it again here.
Now I've got video that just runs fluidly. These splits don't actually create a visual break there. But I can go ahead and adjust the audio for each of these sections separately. If I go ahead and do audio adjustment and bring the volume down just on this clip. So now as I play it, it'll get silent there and then the volume will return as soon as the end of the clip is reached and it goes on to the next section.
If you want to go further than that, you can always finish up your editing in iMovie and then go ahead and bring it into Garage Band and do all the audio editing in there. I'll take a look at that in a future episode. Till next time, this is Gary Rosenzweig with MacMost Now.

Yes, but the audio must go over something — even a plain background. You can’t have a video with no video :)

David H.

1/22/11 @ 6:16 pm

In iMovie 09, will I be able to raise and lower the volume of a music track to accommodate when someone is talking and then not talking? Seems like I would have to split the audio tracks and then edit for fade? Can I fade just to reduce, or are all the fades absolute in and out completely? This was a very helpful video.

But I can see that, if it works, it’ll do what I want. Thanks for alerting me to that.

Shano

2/3/11 @ 2:39 pm

Awesome tutorial Gary,most helpful. Question? When burning to disc I want to set the playback volume on the disc to a level not too loud? I’ve noticed on playback in DVD players the volume is way too loud compared to the volume set on the television?

You can adjust the volume of any track in iTunes by getting its info — it is one of the options. But I am not sure if that changes the volume of the track when burned to CD. There are some options, I think, you get when you choose to create a CD, maybe?